Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details)		1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 30, 2014	May 03, 2019 USD ($)	Jun. 26, 2019 USD ($) restaurant shares	Jun. 27, 2018 USD ($) restaurant	Jun. 26, 2019 USD ($) restaurant supplier segment shares	Jun. 27, 2018 USD ($) restaurant	Dec. 27, 2017 USD ($) supplier	Jun. 26, 2019	Jun. 26, 2019 USD ($)	Dec. 26, 2018 USD ($)
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Depreciation			$ 4,500,000	$ 4,300,000	$ 9,200,000	$ 8,600,000
Number of operating segments | segment					1
Treasury Stock, Value, Acquired, Cost Method			14,943,000		$ 18,326,000
Total amount of outstanding debt									$ 85,000,000
Cash available				13,085,000		13,085,000	$ 8,550,000		11,281,000	$ 6,969,000
Recovery of securities lawsuits related legal expenses			(10,000,000)	(2,429,000)	(10,000,000)	(4,063,000)
Proceeds from Divestiture of Businesses					4,770,000	0
Gain (Loss) on Disposition of Business			(927,000)	0	(5,051,000)	0
Proceeds from Long-term Lines of Credit					26,000,000	6,000,000
Asset Impairment Charges			227,000	1,700,000	227,000	1,708,000
Property and equipment owned, net									91,259,000	104,145,000
Closed-store reserve expense (recovery)				2,300,000	0	5,074,000
Unrecognized tax benefits, accrual of interest or penalties									0	$ 0
Unrecognized tax benefits, interest or penalties expenses			0	0	0	0
Percentage of cash savings in taxes realized as a result of utilizing net operating losses payable to pre-IPO stockholders	85.00%
Income tax receivable agreement (income) expense			(94,000)	$ 712,000	$ 77,000	$ (206,000)
Stock Repurchase Program, Authorized Amount									30,000,000
Stock Repurchase Program Expiration Date					Mar. 25, 2020
Indefinite-lived Intangible Assets
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Asset Impairment Charges			$ 0
Supplier Concentration Risk
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of suppliers | supplier					1		1
Supplier Concentration Risk | Accounts Payable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration					37.10%
Supplier Concentration Risk | Supplier One | Accounts Payable
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration							36.00%
Supplier Concentration Risk | Largest Supplier One | Purchased
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration			30.30%	29.10%	28.80%	28.60%
Geographic Concentration Risk | Revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration			100.00%	100.00%	100.00%	100.00%
Fair Value, Measurements, Nonrecurring
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Asset Impairment Charges			$ 227,000	$ 1,708,000
Property and equipment owned, net				0		$ 0			0
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Nonrecurring
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment owned, net				0		0			0
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Nonrecurring
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment owned, net				0		0			0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Property and equipment owned, net				$ 0		$ 0			$ 0
Credit Agreement Two Thousand Eighteen | Subsequent Event
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Proceeds from Long-term Lines of Credit		$ 8,000,000
Los Angeles | Geographic Concentration Risk | Revenue
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration			69.30%	68.50%	69.30%	68.80%
TEXAS
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants closed			1	2		4
ARIZONA
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants				1		1		7
CALIFORNIA
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants			1		1			4
Number of restaurants closed			1
closed store [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Operating Lease, Expense			$ 300,000		$ 600,000
Common Stock [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Treasury Stock, Shares, Acquired | shares			(1,303,282)		(1,558,836)
Treasury Stock, Value, Acquired, Cost Method			$ (13,000)		$ 15,000
Additional Paid-in Capital [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Treasury Stock, Value, Acquired, Cost Method			$ (14,930,000)		$ 18,311,000
Entity Operated Units
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant			200		200
Franchised Units
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of restaurants | restaurant			284		284